Slotted ground-plane used as a slot antenna or used for a pifa antenna

ABSTRACT

A wireless device includes a ground plane with at least two portions. On each of the at least two portions at least one connecting means is provided. The two connecting means are connected with an electric component for connecting the at least two portions of the ground plane. The ground plane is partially covered with an insulating material and the connecting means are given by a part of the ground plane which is not covered by any insulating material.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation application of U.S. patentapplication Ser. No. 11/884,991. U.S. patent application Ser. No.11/884,991 is a national-stage filing of International PatentApplication No. PCT/EP2006/060766. International Patent Application No.PCT/EP2006/060766 was filed on Mar. 15, 2006. International PatentApplication No. PCT/EP2006/060766 claims priority from European PatentApplication EP 05005540.9, which was filed on Mar. 15, 2005. U.S. patentapplication Ser. No. 11/884,991, International Patent Application No.PCT/EP2006/060766, and EP 05005540.9 are incorporated herein byreference.

BACKGROUND OF THE INVENTION

History of Related Art

Shaping the ground-plane of a wireless communication device (such as forinstance a mobile phone, a smart phone, a PDA, an MP3 player, headset,USB dongle, laptop, PCMCIA or Cardbus 32 card) has been shown to be auseful technique to improve the radiation characteristics of such adevice. This has been for instance disclosed in WO 03 023900. In severalexamples of the prior-art, at least a portion of such a shapedground-plane includes a slot separating totally or partially at leasttwo conducting regions on said ground-plane. Further there are severalknown antenna systems for wireless devices where the radiating antennaelement is just a slot provided in the wireless device's ground plane.Usually such a ground-plane is embedded in a multilayer printed circuitboard (PCB) which hosts the electronics and other components (forinstance integrated circuits, batteries, handset-camera and speakers,LCD screens, vibrators) of the whole device. In these cases, the desiredshape for the ground-plane can be cost effectively implemented by usingconventional PCB manufacturing techniques.

One of the problems of placing the slot on such a PCB is to make thefine tuning of the frequency response of such a slot, and generally thewhole ground-plane. Although several electromagnetic CAD tools canapproximately model the response of the geometry, usually the finaldesign is tuned experimentally. This involves an iterative process whereseveral PCBs are to be prototyped and produced before closing the finalPCB design. This is a costly process, which in turn might delay thecommercial launching of the project.

On the other hand, embedding a slot in the ground-plane some times isdifficult due to the size of the slot and space constrains. If amultiband response of the slot is desired, then usually the shape of theslot involves several branches with several characteristic lengths thatcan fit the multiple wavelengths. In this later case, again the space isa constraint that can make the solution impractical or unfeasible.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a member for awireless device and/or a wireless device with a ground plane whichallows for an improved design process of wireless devices.

This problem is solved with the member of claim 1 and with the wirelessdevice as of claim 16, 17 and/or 19.

The member for the wireless device is or comprises a ground plane withat least two portions. Those two portions are preferably separated by agap or slot or any other non-conducting part. On each of said portions aconnecting means is provided such as a pad or any other connecting meanssuch as a pin, a solder ball or the like. The connecting means areprovided such that they can be connected with an electric component.With this electric component the two portions of the ground plane areconnectable.

The member may be e.g. a PCB with the ground plane. The ground plane maybe an outer layer of the PCB. In case that said PCB is a multilayerboard (with multiple conductive layers separated by insulating layers)the outer ground layer shields inner layers. The ground plane may alsobe provided as an inner layer of a multilayer PCB.

The connecting means are arranged such that an electric componentmounted thereon bridges over a non-conducting area.

In this way, it is possible to change the electric characteristics ofthe ground plane without, however, reshaping the ground plane. Thedesign of the ground plane may therefore be closed while it is stillpossible to electrically change the ground plane in order to provideimproved radiation characteristics.

The two portions of the ground plane may be connected through the groundplane itself such as by a third portion of the ground plane. They may,however, also be disconnected as long as no electric component isconnecting the two portions.

The connecting means may have a size such that only one electriccomponent may be connected thereon. The connecting means, however, mayalso be shaped such that more than one electric component can beprovided thereon. The connecting means may e.g. extend without anydiscontinuity at least along one fifth, fourth, third or half or twothirds, three fourth, three fifth, four fifth or along the entire of thelength of one edge of a slot or gap. The two connecting means may alsobe given by two joint parts of a connecting means which extends aroundan end of a slot, such that one uninterrupted portion of the connectingmeans is provided on both sides of the slot. Then it is still possibleto bridge the slot by an electric component. The connecting means mayalso extend continuously all along the edge of a slot such that the twoconnecting means are given by two parts on different sides of a slot.

The ground plane may for example comprise a slot and the two portionsare provided on different sides of the slot. The slot may penetrate allthrough the ground plane or may only partially penetrate into the groundplane. In the latter case, the two portions are still connected by athird portion of the ground plane, while if the slot penetrates allthrough the ground plane, the two portions are not connected by anotherportion of the ground plane.

The slot may have only one part. The slot may also comprise severalparts such as two, three or more parts. One part may branch off anotherpart and one, two, three or more parts branching off another part may begiven.

The slot may be given in order to enhance radiation characteristics ofthe wireless device. The slot length may define an operating frequencyand/or the slot may be electromagnetically coupled to an antenna elementin order to improve the radiation characteristics of the antenna elementand therefore of the antenna system as a whole. The electric componentmay be provided for fine tuning the electric characteristics of the slotand/or ground plane. It may also be provided to define the basicelectric characteristics of the slot e.g. by a short circuit element. Inthis case an additional electric component may be provided in order tofine tune the electric properties of the slot and/or ground plane.

The connecting means are preferably provided around the edges of theslot. This means that they are located at the edge of the slot and aredistributed around the border of the slot. They may be provided directlyat the edge or also a little bit separated from the edge. Further, theymay be evenly distributed at least on one side or on two sides of theslot along the length of the slot, but they may also be unevenlydistributed at least on some portions of the edge of the slot.

One, both or each of the portions of the ground plane may have multipleconnecting means such as more than two, three, four, five, seven, ten,fifteen, twenty, thirty, forty or fifty connecting means or less thanany of those given numbers. This allows for more flexibility whenchanging the electric characteristics of the ground plane by connectingthe electric component(s).

The ground plane, furthermore, has one, two, three or more connectingmeans for connecting the ground plane to a feeding and/or radiatingelement. In some antenna configurations the radiating element may e.g.be short-connected to the ground plane.

The member preferably comprises an insulating material which ispartially covering the ground plane. With this insulating material it ispossible to define the connecting means by leaving part of the groundplane uncovered. In this way it is easily and cheaply possible to definethe different connecting means. The insulating material may be e.g. apaint, a coating, a foil and can be made of e.g. a resin.

The insulating material is preferably further provided such that it ispresent between different connecting means such that they are clearlyseparated. This allows for well defined locations of the connectingmeans such that if the electric component is provided on the connectingmeans at slightly different positions due to production tolerances, thenthe portions of the ground plane which are connected are, however, stillclearly defined. Thereby it is possible to avoid a major dependence onthe electric characteristics of the ground plane due to fabricationtolerances in the exact location of the electric component.

The connecting means may, however, also be given by a pad that isconnected to the ground plane with a via, that extends into a multilayerPCB. In this case the ground plane is provided as an inner conductivelayer.

The electric component may e.g. be a resistor, a short circuit element,a capacitor, a conductor, a filter, a diode, a transistor, a switch orany other radio frequency device as explained in more detail below.

The connection between the different portions may be established by morethan one electric component e.g. by two, three or more electriccomponents. Two or three or more of those components may be arranged inseries and/or parallel. Further, the electric components may be thesame, different or some of them may be the same or different. Thisallows for very increased flexibility in adapting the electricproperties of the ground plane.

The ground plane may be coupled to one or more antenna elements. Thecoupling may be by direct electric connection or by coupling withelectric/electromagnetic fields through a separation between the antennaelement/antenna elements and the ground plane. In a preferred mode, theantenna element is an inverted F antenna (IFA) or, more preferably, aplanar inverted F antenna (PIFA). The antenna may be a patch antennasince this allows for a compact design of the wireless device.

The connecting means and the antenna element may be provided on the sameside or on different sides of the ground plane/PCB.

Preferably, the slot is placed substantially close to the antennaelement such that the coupling between the slot and the antenna elementis enhanced. Preferably the slot would be placed at a location which isprovided by an orthogonal projection of the antenna onto the groundplane. Preferably, the slot is provided substantially aligned with anedge of the antenna and/or of the ground plane.

A feeding terminal and a shorting terminal of said antenna element(s)may be provided on the same portion of the ground plane but they mayalso be provided on the two different portions of said ground plane.

Preferably the member further comprises or is given by a circuit boardon which or in which the ground plane is provided. The circuit board maybe a multi-layer circuit board wherein one conductive layer forms theground plane.

The ground plane may host other components of the wireless device suchas other electronic parts, a frequency generator/receiver for thewireless operation, other integrated circuits, a battery, a key pad, aspeaker, a camera, a display, a vibrator, etc.

The ground plane is not necessarily “plane” since it may also be curved,bent or provided with steps. Sometimes, instead of to a ground plane, itis also referred to a ground counterpoise, which refers to the same.

The electric component preferably is or comprises a surface mountdevice. In fabrication technologies of wireless devices, surfacemounting of devices is common and, therefore, in the production of themembers for wireless devices surface mount technology is highlyfavorable. The electric component, however, may also be or comprise abonding wire. This is suitable, in particular, for providing a shortcircuit element or a good electric connection between two other electriccomponents used for tuning the electrical ground plane properties.

The wireless device of the present invention comprises a member asmentioned beforehand. In that wireless device in general one or morepair of connecting means may be connected by an electric component. Itis, however, also possible, that none of the connecting means isconnected to an electric component in case that the ground plane fitswith the electrical requirements without any electric component.

In general some of the connecting means and in particular the majoritythereof are unconnected since they only provide for the possibility toconnect an electric component but in general there will be manyconnecting means a few of which are chosen from for connection, while alarger number will be left unconnected, since a connection thereof doesnot provide for the desired electrical characteristic of the groundplane.

Alternatively, the present invention consists of a wireless device (suchas for instance a mobile phone, a smartphone, a PDA, an MP3 player,headset, USB dongle, laptop, PCMCIA or Cardbus 32 card) including areconfigurable ground-plane. This is achieved by interconnecting anelectric component with at least two portions of the conducting surfaceof said ground-plane. Usually, the interconnection is preferably madebetween two portions of the ground-plane, said portions being separatedby a gap or a slot on the conducting surface of said ground-plane. Saidcomponent modifies the radiation frequency response of said slot and thecombination of said slot with said electric component modifies theelectromagnetic and radiation frequency response of the antenna systemand therefore of the entire wireless device.

Another aspect of the invention refers to the above-describedreconfigurable ground-plane for a wireless device.

Such a general electric component, is for instance chosen from thefollowing set: a resistor, a short circuit element, a capacitor, aninductor, a filter, a diode, a transistor, a switch or other kind ofradio frequency devices. Any combination of them is possible.

Generally, the ground-plane within said wireless device can include morethan one gap or slot separating totally or partially several groundingareas on said ground-plane. One or more electric components can beplaced in one or more of said slots in said ground-plane.

In some embodiments, the present invention is used to enhance theradiation characteristics of the wireless device. For instance, the slotlength can be tuned to resonate at a desired wavelength, such radiationis enhanced around such a particular wavelength. This can be used toincrease the number of operating frequency bands of the wireless device,to increase the bandwidth of one or more of the bands, or a combinationof both effects. When no component is applied, typically the slot willresonate at an odd multiple of a quarter wavelength (if the slot isopened at one tip and shorted at the opposite one), or at a multiple ofhalf a wavelength (if the slot has both ends shorted or opened withrespect to the ground-plane). By introducing an electric componentaccording to the present invention, this behavior can be modified. Inparticular, the following effects, or a combination of them can beobtained in several arrangements:

EMBODIMENT 1

The component is a short circuit (or a low resistance component) e.g.interconnecting opposite edges of the slot. The effect is that the slotbecomes electrically shorter and the resonance frequency of the slot ischanged, typically to shorter wavelengths (higher frequencies).

EMBODIMENT 2

The component is a capacitor e.g. interconnecting opposite edges of theslot. Such a capacitor will have a frequency selective behavior,shorting both edges at a desired operating frequency. As a result, theslot will change its resonant frequency and/or introduce a newnon-harmonic resonance that might be used to tune multiple frequencybands in the wireless device. Also, a bandwidth enhancement at aparticular frequency band can be obtained by combining the naturalresonance of the unloaded slot (a slot without any electric component),and the reactive response of the electric component. This arrangementcan be used advantageously for a shortened length of the slot in case ofspace constraints on the PCB.

EMBODIMENT 3

The component is an inductor e.g. interconnecting opposite edges of theslot. Such an inductor will have a frequency selective behavior,shorting both edges at a desired operating frequency. As a result, theslot will change its resonant frequency and/or introduce a newnon-harmonic resonance that might be used to tune multiple frequencybands in the wireless device. Also, a bandwidth enhancement at aparticular frequency band can be obtained by combining the naturalresonance of the unloaded slot, and the reactive response of theelectric component. This arrangement can be used advantageously for ashortened length of the slot in case of space constraints on the PCB.

EMBODIMENT 4

The component is a filter e.g. interconnecting opposite edges of theslot. Such a filter will allow some frequencies to cross over the slotwhile rejecting others. As a result, the slot will change its resonantfrequency and/or introduce a new non-harmonic resonance that might beused to tune multiple frequency bands in the wireless device. Also, abandwidth enhancement at a particular frequency band can be obtained bycombining the natural resonance of the unloaded slot, and the reactiveresponse of the electric component. This arrangement can be usedadvantageously for a shortened length of the slot in case of spaceconstraints on the PCB.

EMBODIMENT 5

The component is a switch, a diode (such as for instance a PIN diode, ashotky diode) or a transistor that can be for instance used to switch onand off the connection between the two portions such as the two oppositeedges of the slot. Again, this can be used to switch on and off some ofthe resonance frequencies of the slot, which in combination with theshape of the ground plane and the radiating elements (such as forinstance antenna elements) placed over or coupled to such aground-plane, can modify the frequency response (number of bands,bandwidth, impedance matching characteristics) of the wireless device.Commutation or combination of transmitted and/or received multiple radiosignals can be obtained this way.

The switch or transistor can be connected to an electronic processor ofthe wireless device which can select the desired electric characteristicof the ground plane.

The components and effects mentioned in the above embodiments can becombined in any way.

EMBODIMENT 6

In a preferred embodiment, which may be combined with any of the aboveembodiments, at least one of the slots in such a ground-plane willinclude one or more pads grounded at one or more of the edges of saidslot, in such a way an electrical/electronic/RF component can be placedover the slot and interconnecting both sides of the slot. In otherembodiments, the wireless device includes more than one of those pads orpair of pads around the slot, such that the optimum placement of thecomponent can be tested and fixed without changing the prototyping andmanufacturing of the PCB.

This is an example of a PCB in a wireless device including severalgrounded pads around the slot area. At least one electric component(such as for instance a surface mounted device, SMD) may connect twopads, one of those pads placed on one side and the other on the otherside. The component can be generally any electric component, butpreferably is chosen from the examples described in embodiments onethrough five (for instance resistor, a short circuit element, acapacitor, an inductor, a filter, a diode, a transistor, a switch orother kind of radio frequency devices). The electric component orcomponents can be flexibly mounted in any of the pre-fixed pads untilthe desired frequency response and radiation characteristics of thewireless device are obtained. Some additional feeding pads for anantenna device may be provided (for instance a short and a feeding padfor a PIFA antenna are shown in FIG. 5 without any limiting purpose).

EMBODIMENT 7

In other embodiments, more than one component is connected to the slot.For instance, those components can be connected in a serial or cascadingconnection and/or, in parallel, through a pair or multiple pads. Thisapplies to any of the components mentioned above, in particular to thecomponents of the above described embodiments.

EMBODIMENT 8

In this embodiment, which can be combined with any of the aboveembodiments, the slot in the ground-plane is coupled to an antennadevice. Although the antenna can be any type of antenna (a monopole, adipole, a patch, a dielectric antenna or alike), usually a patchantenna, and more specifically a planar inverted F antenna (PIFA) willbe preferred. Although the slot can be placed generally in any place ofthe PCB, preferably it will be placed substantially close to the antennaelement such that the electromagnetic coupling between slot and antennaelement is enhanced. In a preferred embodiment the slot will be placedunder the antenna. In another embodiment, the slot will be placedsubstantially aligned with at least one of the edges of the antenna. Areconfigurable wireless device with a reconfigurableantenna+ground-plane set is obtained by placing one or more pads closeto the edge of such at least one slot.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the cushion of the present inventionmay be obtained by reference to the following Detailed Description, whentaken in conjunction with the accompanying Drawings, wherein:

The attached drawings comprise the following figures:

FIG. 1 shows a member 1 for a wireless device;

FIG. 2 shows the combination of the member for a wireless device and anelectric component;

FIG. 3 shows different configurations of slots and connecting means;

FIG. 4 shows a preferred embodiment of the member for a wireless device;

FIG. 5 shows a PCB and a reconfigurable slot (Embodiment 6). The PCB canbe tested with the component placed in the several positions to decidewhich is the optimum position for the desired radio frequency response;

FIG. 6 shows a PCB of a wireless device and a reconfigurable slot(Embodiment 7). In this particular example, two SMD components arecascaded to interconnect two pads at opposite edges of the slot. Forinstance this can be an inductor and a capacitor, to make a serial LCfilter or resonator;

FIG. 7 shows a PCB of a wireless device and a reconfigurable slot(Embodiment 7). In this particular example, two SMD components aremounted in parallel to interconnect the two opposite edges of the slot.For instance this can be an inductor and a capacitor, to make a shunt LCfilter or resonator;

FIG. 8 shows a reconfigurable slot in a ground-plane coupled to a PIFAantenna device;

FIG. 9 a shows a reconfigurable slot in a ground-plane coupled to a PIFAantenna device. Short and feeding pads of the antenna are placed atopposite sides of the slot;

FIG. 9 b shows the reconfigurable slot in a ground-plane in particularuseful for cases without a separate antenna element, where the slot actsas an antenna; and

FIG. 10 shows a wireless device (here a mobile telephone) in combinationwith a member for a wireless device.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS OF THE INVENTION

Various embodiments of the present invention will now be described morefully with reference to the accompanying drawings. The invention may,however, be embodied in many different forms and should not be construedas limited to the embodiments set forth herein; rather, the embodimentsare provided so that this disclosure will be thorough and complete, andwill fully convey the scope of the invention to those skilled in theart.

FIG. 1 a shows in a three dimensional schematic diagram a part of amember 1 for a wireless device. The member 1 comprises two conductinglayers 2, 3 which form two conducting portions of the ground plane.Those two portions are separated by a slot 6 where no conducting layeris provided. The conducting layers 2, 3 are provided on a PCB board 7.

On the two sides of the slot 6, contact pads 4, 5 are provided. They arein such an opposite relation that they can be interconnected with anelectric component which is oriented essentially perpendicular to theslot 6 at the location between the two connecting means 4, 5. A cutsection along line bb of FIG. 1 a is shown in FIG. 1 b. On the circuitboard substrate 7, which may be a conventional circuit board, twoconducting layers 2, 3 are provided which are separated by a slot 6.Those conducting layers 2, 3 are each covered partially by an insulatingmaterial 8, 9, respectively. The insulating materials 8, 9 do not coverentirely the portions 2, 3 and some part of the portions 2, 3 are leftblank. Those parts are one example of the contact pads 4, 5 as shown inFIG. 1 a.

The outer shape of the member 1 is not shown in FIG. 1 a since the outershape may essentially be any shape. It may be rectangular, circular,elliptic, irregularly shaped or any other shape. Usually it will beadapted to the shape of the wireless device.

FIG. 2 shows the member 1 of FIG. 1 where an electric component 10 isadded. As can be seen in FIG. 2 a and FIG. 2 b, this component bridgesthe slot 6 and is connected to the two pads 4, 5 thereby connecting thetwo ground plane portions 2, 3. The electric connection between each padand the electric component may be established by solder.

In FIGS. 1 and 2, the two pads 4, 5 are provided on the edge of the slot6. However, some insulating material may also be provided directly atthe edge of the slot 6 such that the contact pads 4, 5 are provided at acertain distance from the slot 6. However they should not be furtheraway from the slot 6 than e.g. the size of the pad 4, 5 or of the slotin a direction perpendicular to the slot 6. When providing the slot withconnecting means at both sides, the manufacturing process itself mayimpose manufacturing tolerances that may not make possible and/orconvenient to arrange them closer than a certain distance d.

FIG. 3 shows schematic views of alternative formations of the slot.

In FIG. 3 a, the slot 6 is shown which only partially penetrates intothe ground plane. The portion 12 of the ground plane is provided whichconnects the portions 2 and 3 which are separated by the slot 6.

In FIG. 3 a, at least one end of the slot 6 coincides with the end ofthe ground plane 2, 3 (see FIG. 3 a bottom). The slot depicted in FIG. 3a features an open end and a closed end. The slot may also be providedentirely within the ground plane which means that the slot is surroundedby the ground plane at all ends of the slot, and therefore the slot 6has at least two closed ends.

In FIG. 3 b it is shown that the slot is not necessarily straight butmay also be bent or curved.

In FIG. 3 c, it is shown that the width of the slot 6 may be non-uniformdue to the protrudence or protrusion of one ground plane portion 3.Independent of the protrusions or the non-uniform width of the slot thisFig. also shows an example where the connecting means 4 a, 4 b, 4 c and5 a, 5 b, 5 c are spaced at different spacing along the slot since e.g.connecting means 4 b and 4 c are closer together than 4 a and 4 b.

In FIG. 3 d it is shown that the ground plane portions 2, 3 on bothsides of the slot 6 may have protrusions. Preferably, those protrusionsare opposite to each other. They may, however, also be offset along theslot 6.

The pads 4 a, 4 b, 4 c, 5 a, 5 b, 5 c are provided on those protrusions.In this way, the pads are provided at narrow portions of the slot 6.

In FIG. 3 e, the case is shown where the slot has a curved edge which isnot composed by straight lines. Here the pads 4 a, 4 b, 5 a, 5 b arealso provided at the narrow portions of the slot 6. They may, however,also be provided at wider portions of the slot 6 (the same applies toFIGS. 3 c and 3 d).

In FIG. 3 f two elongated connecting means 4,5 are shown which extendalong the slot 6. They have a length of more than half of the length ofthe slot 6. On such connecting means the electric component(s) may beplaced anywhere such that a continuous fine tuning of the electriccharacteristics is possible by choosing the location of the electriccomponent freely along the length of the connecting means.

In FIG. 3 g the case is shown where the two connecting means 4, 5 aregiven by two portions of a continuous connecting means, which areprovided on two different sides of the slot 6 or gap. The connectingmeans 4, 5 extends around the end of the slot 6 (in FIG. 3 g the upperend).

In FIG. 4, a particular case of a slot 6 is shown where at least some ofthe contact pads are provided in corners formed by the slot 6. As can beseen in FIG. 4, the contact pads 13 and 18 are in corners. The contactpad 16 is provided at the end of a protrusion of the ground planeportion 2. With this configuration, an electric component may be locatede.g. connecting the pad 16 with the pad 13, 15 or 18. The spacingbetween the pad 16 relative to the pad 13, 15 and 18 is always the samesuch that electric components with the same size can be located at anyof those possible three combinations. Also, it would be possible toconnect pad 13 with pad 16 and at the same time connect pad 16 with pad15 or 18 with another device. Pad 13 may alternatively also be connectedwith an electric component 20 (dashed line) with pad 14. As an exampleonly, an electric component 19 is provided in order to connect pad 16and pad 18.

The example of FIG. 4 shows that with 6 pads (13 to 18), 5 differentpossible connections between pads on different sides of slot 6 arepossible. In general therefore, the pads may be arranged in such a waythat one pad on one side of the slot may be connected to at least two orthree other pads on the other side of the slot with identicalcomponents.

In the following figures the ground plane shapes have an outer shape ofa rectangle, as an example only.

FIG. 5 shows a special case of a ground plane 2, 3 where a slot isprovided with one end at one edge of the ground plane (open end) andterminates with another end within the ground plane (closed end). Thetwo portions 2, 3 are therefore connected by a portion of the groundplane.

Portions 2, 3 each are provided with a multiple number of pads, where inFIG. 5, as an example, each side is provided with seven pads. All thepads are located on or close to the edge of the slot 6. The number ofpads on both sides of the slot here is equal. The number may, however,also be different.

Between pads opposite to each other across the slot 6, an electriccomponent 10 may be provided bridging the slot 6.

Depending on the pads which are interconnected by the component 10, theslot in the ground plane and thus the slotted ground plane will havedifferent electric characteristics. As explained above, by connectingdifferent pads on each side of the slot 6, different electriccharacteristics can be achieved.

On one portion 2 of the ground plane, a short connection (pad) 21 and afeeding connection (pad) 22 is provided. The feeding connection isprovided for connecting the antenna radiating element to a highfrequency generator/receiver and the grounding connection (pad) isprovided in order to ground a portion of the antenna radiating elementwith the ground plane. This may be useful for IFA or PIFA antennas. Theposition of the connections 21 and 22 may be interchanged. Further theymay be positioned closer to or in the middle of the upper end of theground plane portion 2 or closer to the opposite upper end (upper leftcorner in FIG. 5).

In FIG. 6, a case is shown where two electric components 10 a, 10 b areconnected in series in order to connect two pads 4, 5 each of which isprovided on a portion 2, 3 of the ground plane.

In FIG. 7, the case is shown where two electric components 10 a, 10 bare provided in parallel in order to connect the two portions 2, 3 ofthe ground plane across the slot 6.

In FIG. 8 a the configuration of the ground plane in combination with anantenna is shown.

The antenna element 26 is provided at a certain distance from the groundplane 2, 3. Further, the antenna element 26 is provided close to an edgeof the ground plane. The slot 6 is provided close to the same edge. Inthis way, the antenna element and the slot 6 are close together whichallows for a good electromagnetic coupling.

The antenna element 26 is connected with one terminal 24 to one portion3 and with another terminal 25 to another portion 2 of the ground plane.The terminal 24 is connected to the feeding pad 23 and the otherterminal 25 is grounded to the ground plane.

The slot 6 of the ground plane may act as an antenna. This slot antennaand the antenna element 26 may both be excited by the same feedingconnection 23.

As shown in FIG. 8 b additionally a number of connecting means 4 a, 4 b,4 c, 5 a, 5 b, 5 c (connecting pads) are provided so that the radiatingcharacteristics of the slot can be adjusted.

The views in the middle and on the right hand side of FIGS. 8 a and 8 bshow a view perpendicular onto the ground plane and the slot 6. Theantenna element 26 is located in front of that slot 6. The lines coveredby the antenna element 26 are shown in dashed lines. Further thelocation of the connecting means (grounded pads) 4, 5 are shown. Theantenna element 26 and the connecting means 4, 5 are provided on thesame side (before/behind) of the ground plane. In general, however, theconnecting means 4, 5 and the antenna element 26 may be provided onopposite sides (before/behind) of the ground plane 2, 3.

In FIG. 9 a, the case is shown where the feeding connection 22 and theground connection 21 are provided on different sides of the slot 6. Thismeans that they are provided on different portions 2, 3 of the groundplane. In this case the slot may be the antenna itself. No additionalradiating element may be required. Nevertheless a further antennaelement may be provided in order to have further operating frequenciesavailable or to improve the radiation characteristics of the combinationof the slot and the antenna element.

As shown in FIG. 9 b the feeding connection 22 and/or the groundconnection 21 can be placed between connecting means 4, 5 in a directionalong the slot. This arrangement can be in particular useful, when noseparate antenna element is provided and the slot 6 acts as an antenna.As shown in the arrangement in FIG. 9 a the feeding connection 22 and/orground connection 21 may nevertheless also be provided on one side (in adirection along the slot) of the connecting means 4, 5 only.

In general the feeding connection 22 and/or the ground connection 21 maybe placed close to an end of the slot (in particular a closed end), atthe middle of the slot or spaced from the end of a slot by a third orfourth part of the length of the slot along the slot or within anyinterval of those values.

As shown in FIGS. 8 and 9 the feeding connection 22, 23 is preferablyplaced on the portion 3 of the ground plane that is larger than theother portion 2, since on this larger portion the frequencygenerator/receiver (not shown) may be placed conveniently and may suchbe placed very close to the feeding connection 22, 23. The feedingconnection 22, 23 and/or the ground connection may nevertheless also beprovided on the other portion 2, 3 in comparison to FIGS. 8 and 9.

In any of the above shown examples, the slot 6 itself may function as anantenna. The slot has a characteristic length which allows the slot toresonate at a resonance frequency. Therefore it is not always necessarythat a separate antenna element is provided.

In FIG. 10, a mobile phone (also called a cellular phone) 30 is shown.Within that cellular telephone, which here represents any wirelessdevice, a member with two ground plane portions 2, 3, a slot 6 and anelectric component 10 bridging the slot 6 is shown.

In a preferred arrangement, the antenna is a PIFA antenna, with oneshort (direct electric contact between the antenna element and theground plane) at one edge of the slot and the feeding point at theopposite edge. This enables a combined excitation of both the slot andthe antenna, such that a broadband, multiband or combination of botheffects is obtained. Such an arrangement becomes also useful to matchthe impedance of the antenna at one or more frequency bands.

In some embodiments, the slot can be excited with one or more springcontacts or metallic bridges crossing over the slot, which means, thatthe a spring contact is used to establish an electric connection throughwhich feeding is carried out. By placing several pads at opposite sidesof the slot according to the present invention, an adjustment of theoptimum slot excitation can be obtained without changing the layout ofthe PCB.

Generally, the present invention can be arranged inside several kinds ofwireless devices to enhance its radiation characteristics. A multiband,multi systems device with enhanced performance (bandwidth, number ofbands, radiation efficiency, sensitivity, gain) is obtained. In somepreferred embodiments the wireless device is operating at one, two,three or more of the following communication and connectivity services:GSM850, GSM900, GSM1800, PCS1900, GSM450, UMTS, WCDMA, CDMA, Bluetooth,WLAN, WiFi, UWB, ZigBee, GPS, Galileo, SDARs, XDARS, WiMAX.

It should be stressed that the slot does not necessarily need to have alinear shape with a constant width. Other forms such as space-fillingcurves as described in the PCT publication WO 0154225, fractal, ormultilevel structures as described in the PCT publication WO 0122528 arepossible within this invention. Non-uniform width slots are possible aswell. In the case of non-uniform width slots, the component orcomponents will be preferably placed in those regions where the distancebetween opposite edges of the slot is minimum.

The ground-plane can feature generally any shape, such as aspace-filling (see for instance WO 0154225), a multilevel (see forinstance WO 0122528), a polygonal, conformal or fractal shape.

While the invention has been described with respect to specific examplesincluding presently preferred modes of carrying out the invention, thoseskilled in the art will appreciate that there are numerous variationsand permutations of the above described systems and techniques that fallwithin the spirit and scope of the invention as set forth in theappended claims.

1. A wireless device comprising: a ground plane, the ground planecomprising: a first portion; a second portion; and wherein the firstportion and the second portion defines a slot therebetween; an antennaelement, the antenna element operating in cooperation with the groundplane; wherein the first portion comprises a first connecting means andthe second portion comprises a second connecting means; and wherein thefirst connecting means and the second connecting means are arranged withrespect to the slot so as to define a plurality of locations along aphysical length of the slot on which an electrical component can beplaced to establish electrical contact between the first connectingmeans and the second connecting means modifying an electrical length ofthe slot.
 2. The wireless device of claim 1, wherein the ground planecomprises a third portion, the third portion connecting the firstportion and the second portion of the ground plane.
 3. The wirelessdevice of claim 1, wherein the first connecting means and the secondconnecting means are provided on opposite sides of the slot.
 4. Thewireless device of claim 3, wherein at least one of the first connectingmeans and the second connecting means comprises a plurality of pads. 5.The wireless device of claim 3, wherein at least one of the firstconnecting means and the second connecting means is an elongatedconnecting means.
 6. The wireless device of claim 2, wherein the thirdportion defines an end to the slot, wherein the first connecting meansand the second connecting means are elongated connecting means connectedaround the end of the slot.
 7. The wireless device of claim 3, wherein afirst side of the slot is defined by a first plurality of edges of thefirst portion of the ground plane, and wherein a second side of theslot, opposite to the first side, is defined by a second plurality ofedges of the second portion of the ground plane.
 8. The wireless deviceof claim 1, wherein the first connecting means and the second connectingmeans define at least three locations along the physical length of theslot on which the electrical component can be placed to establishelectrical contact between the first connecting means and the secondconnecting means modifying the electrical length of the slot.
 9. Thewireless device of claim 1, wherein the ground plane is partiallycovered with an insulating material and wherein the first connectingmeans and the second connecting means are given by a part of the groundplane which is not covered by any insulating material.
 10. The wirelessdevice of claim 9, wherein the insulating material separates differentparts of the ground plane defining the first connecting means and thesecond connecting means.
 11. The wireless device of claim 1, wherein thewireless device comprises at least one electric component thatestablishes electrical contact between the first connecting means andthe second connecting means.
 12. The wireless device of claim 11,wherein the at least one electric component is selected from the groupof electric components consisting of a resistor, a short circuitelement, a capacitor, an inductor, a filter, a diode, a transistor, aswitch, and a radio frequency device.
 13. The wireless device of claim11, wherein the at least one electric component is a surface mountdevice.
 14. The wireless device of claim 11, wherein the at least oneelectrical component modifies the electrical length of the slot so thatthe slot is electromagnetically coupled to the antenna element in atleast one frequency band of operation of the wireless device.
 15. Thewireless device of claim 11, wherein the electrical component modifiesthe electrical length of the slot so that the ground plane is resonantin at least one frequency band of operation of the wireless device. 16.The wireless device of claim 1, wherein the antenna element is selectedfrom the group consisting of an IFA, a PIFA antenna, a patch antenna, amonopole antenna, and a dielectric antenna.
 17. The wireless device ofclaim 1, wherein the antenna element comprises: a feeding terminal; ashorting terminal; and wherein the feeding terminal and the shortingterminal are provided on a same portion of the ground plane.
 18. Thewireless device of claim 1, wherein the wireless device comprises: acircuit board including at least one conductive layer; and wherein theground plane is provided as a conductive layer of the circuit board. 19.A member for a wireless device comprising: a ground plane having atleast two portions; at least one connecting means is provided on each ofsaid at least two portions; wherein the connecting means can beconnected with an electric component for connecting said at least twoportions of said ground plane; and wherein the ground plane is partiallycovered with an insulating material and said connecting means are givenby a part of the ground plane which is not covered by any insulatingmaterial.
 20. A wireless device comprising a ground plane, the groundplane comprising: a first portion, the first portion comprising firstconnecting means and feeding means; a second portion, the second portioncomprising second connecting means and grounding means; wherein thefirst portion and the second portion defines a slot therebetween;wherein the first connecting means and the second connecting means arearranged with respect to the slot so as to define a first plurality oflocations along a physical length of the slot on which an electricalcomponent can be placed to establish electrical contact between thefirst connecting means and the second connecting means modifying anelectrical length of the slot; and wherein the feeding means and thegrounding means are arranged with respect to the slot so as to define asecond plurality of locations along the physical length of the slot onwhich a feeding terminal and a grounding terminal can be connected toelectrically drive the slot as an antenna element.